Sodium bicarbonate and systemic hemodynamics in volunteers anesthetized with halothane

The cardiovascular effects of acute metabolic alkalosis (NaHCO₃) in normal male volunteers anesthetized with halothane were measured. Pure metabolic alkalosis was studied by maintaining the end tidal carbon dioxide tension at 40 torr. In each subject, cardiac index increased and total peripheral resistance decreased after each dose of NaHCO₃. The increased cardiac index was associated with increased central blood volume, left ventricular minute work index, stroke index, and heart rate. Systolic time intervals showed increased myocardial performance. NaHCO₃ administered to volunteers whose hearts were depressed by halothane appeared to cause peripheral vasodilation, volume expansion, and myocardial stimulation. The authors conclude that NaHCO₃ administered during halothane anesthesia decreases total peripheral resistance and may lead to severe hypotension.